Use a combination of follow- and stop-token lists and nesting levels
to better synchronize parser after a syntax error.
Fixes#13319.
Change-Id: I9592e0b5b3ba782fb9f9315fea16163328e204f7
Reviewed-on: https://go-review.googlesource.com/17080
Reviewed-by: Chris Manghane <cmang@golang.org>
This is a translation of the yacc-based parser with adjustements
to make the grammar work for a recursive-descent parser followed
by cleanups and simplifications.
The yacc actions were mostly literally copied for correctness
with better temporary names.
A few of the syntax tests were adjusted for slightly different
error messages (it is very difficult to match the yacc-based
error messages in all cases, and sometimes the new parser could
produce better errors).
The new parser is enabled by default.
To switch back to the yacc-based parser, set -oldparser.
To hardwire the switch back, uncomment "oldparser = 1" in lex.go.
- passes all.bash
- ~18% reduced parse time per file on average for make.bash
- ~3% reduced compile time for building cmd/compile
Change-Id: Icb5651bb9d8b9f66261762d2c94a03793050d4ce
Reviewed-on: https://go-review.googlesource.com/16665
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
const1.go:33: error: integer constant overflow
<similar errors omitted>
const1.go:64: error: division by zero
const1.go:67: error: floating point constant overflow
const1.go:68: error: floating point constant overflow
const1.go:69: error: floating point constant overflow
const1.go:70: error: division by zero
const1.go:71: error: expected integer type
const1.go:77: error: argument 1 has incompatible type (cannot use type int8 as type int)
const1.go:78: error: argument 1 has incompatible type (cannot use type int8 as type int)
const1.go:79: error: argument 1 has incompatible type (cannot use type uint8 as type int)
const1.go:81: error: argument 1 has incompatible type (cannot use type float32 as type int)
const1.go:82: error: argument 1 has incompatible type (cannot use type float64 as type int)
const1.go:83: error: floating point constant truncated to integer
const1.go:85: error: argument 1 has incompatible type (cannot use type float64 as type int)
const1.go:86: error: argument 1 has incompatible type (cannot use type string as type int)
const1.go:87: error: argument 1 has incompatible type (cannot use type bool as type int)
const1.go:90: error: const initializer cannot be nil
const1.go:91: error: expression is not constant
const1.go:92: error: expression is not constant
const1.go:93: error: invalid constant type
const1.go:94: error: invalid constant type
fixedbugs/bug462.go:17: error: unknown field 'os.File' in 'T'
fixedbugs/issue3705.go:9: error: cannot declare init - must be func
fixedbugs/issue4251.go:12: error: inverted slice range
fixedbugs/issue4251.go:16: error: inverted slice range
fixedbugs/issue4251.go:20: error: inverted slice range
fixedbugs/issue4405.go:11: error: invalid character 0x7 in identifier
fixedbugs/issue4405.go:12: error: invalid character 0x8 in identifier
fixedbugs/issue4405.go:13: error: invalid character 0xb in identifier
fixedbugs/issue4405.go:14: error: invalid character 0xc in identifier
fixedbugs/issue4429.go:15: error: expected pointer
fixedbugs/issue4517d.go:9: error: cannot import package as init
fixedbugs/issue4545.go:17: error: invalid context-determined non-integer type for left operand of shift
fixedbugs/issue4545.go:16: error: incompatible types in binary expression
fixedbugs/issue4610.go:15: error: expected ';' or '}' or newline
fixedbugs/issue4610.go:16: error: expected declaration
fixedbugs/issue4654.go:15: error: value computed is not used
<similar errors omitted>
fixedbugs/issue4776.go:9: error: program must start with package clause
fixedbugs/issue4776.go:9: error: expected ';' or newline after package clause
fixedbugs/issue4813.go:31: error: index must be integer
<similar errors omitted>
fixedbugs/issue4847.go:22: error: initialization expression for 'matchAny' depends upon itself
fixedbugs/issue5089.go:13: error: redefinition of 'bufio.Buffered': receiver name changed
fixedbugs/issue5089.go:11: note: previous definition of 'bufio.Buffered' was here
fixedbugs/issue5172.go:17: error: reference to undefined field or method 'bar'
fixedbugs/issue5172.go:18: error: reference to undefined field or method 'bar'
fixedbugs/issue5172.go:12: error: use of undefined type 'bar'
fixedbugs/issue5358.go:16: error: argument 2 has incompatible type
fixedbugs/issue5581.go:29: error: use of undefined type 'Blah'
funcdup.go:10: error: redefinition of 'i'
funcdup.go:10: note: previous definition of 'i' was here
<similar errors omitted>
funcdup2.go:10: error: redefinition of 'i'
funcdup2.go:10: note: previous definition of 'i' was here
<similar errors omitted>
slice3err.go:20: error: middle index required in 3-index slice
<similar errors omitted>
slice3err.go:20: error: final index required in 3-index slice
<similar errors omitted>
slice3err.go:21: error: final index required in 3-index slice
slice3err.go:46: error: invalid 3-index slice of string
<similar errors omitted>
slice3err.go:57: error: inverted slice range
<similar errors omitted>
slice3err.go:62: error: invalid slice index: capacity less than length
slice3err.go:64: error: invalid slice index: capacity less than start
slice3err.go:65: error: invalid slice index: capacity less than start
slice3err.go:66: error: invalid slice index: capacity less than start
slice3err.go:68: error: invalid slice index: capacity less than length
slice3err.go:70: error: invalid slice index: capacity less than start
slice3err.go:80: error: invalid slice index: capacity less than length
slice3err.go:82: error: invalid slice index: capacity less than start
slice3err.go:83: error: invalid slice index: capacity less than start
slice3err.go:84: error: invalid slice index: capacity less than start
slice3err.go:86: error: invalid slice index: capacity less than length
slice3err.go:88: error: invalid slice index: capacity less than start
slice3err.go:99: error: array index out of bounds
<similar errors omitted>
slice3err.go:106: error: invalid slice index: capacity less than length
slice3err.go:107: error: invalid slice index: capacity less than start
slice3err.go:118: error: invalid slice index: capacity less than length
slice3err.go:119: error: invalid slice index: capacity less than start
syntax/semi1.go:10: error: missing '{' after if clause
syntax/semi1.go:10: error: reference to undefined name 'x'
syntax/semi1.go:10: error: reference to undefined name 'y'
syntax/semi1.go:12: error: reference to undefined name 'z'
syntax/semi2.go:10: error: missing '{' after switch clause
syntax/semi2.go:10: error: reference to undefined name 'x'
syntax/semi3.go:10: error: missing '{' after for clause
syntax/semi3.go:10: error: reference to undefined name 'x'
syntax/semi3.go:10: error: reference to undefined name 'y'
syntax/semi3.go:10: error: reference to undefined name 'z'
syntax/semi3.go:12: error: reference to undefined name 'z'
syntax/semi4.go:11: error: missing '{' after for clause
syntax/semi4.go:10: error: reference to undefined name 'x'
syntax/semi4.go:12: error: reference to undefined name 'z'
typecheck.go:12: error: reference to undefined name 'b'
typecheck.go:17: error: reference to undefined name 'c'
typecheck.go:11: error: use of undefined type 'b'
typecheck.go:16: error: not enough arguments
typecheck.go:17: error: not enough arguments
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/41520044
syntax/*: update messages
sliceerr3.go: bizarre new error fixed by deleting a space.
I could have sworn I ran all.bash before submitting the CL that triggered these.
TBR=golang-dev@googlegroups.com
R=golang-dev
CC=golang-dev
https://golang.org/cl/12812044
complit1.go:37:34: error: may only omit types within composite literals of slice, array, or map type
complit1.go:38:19: error: may only omit types within composite literals of slice, array, or map type
complit1.go:18:21: error: slice of unaddressable value
complit1.go:19:10: error: slice of unaddressable value
complit1.go:20:9: error: slice of unaddressable value
convert1.go:28:13: error: invalid type conversion
convert1.go:32:12: error: invalid type conversion (cannot use type string as type Tint64)
convert1.go:36:12: error: invalid type conversion
convert1.go:37:13: error: invalid type conversion
convert1.go:40:11: error: invalid type conversion
convert1.go:41:12: error: invalid type conversion
convert1.go:44:12: error: invalid type conversion
convert1.go:46:13: error: invalid type conversion
convert1.go:48:11: error: invalid type conversion
convert1.go:50:12: error: invalid type conversion
convert1.go:52:6: error: invalid type conversion
convert1.go:53:12: error: invalid type conversion
convert1.go:54:12: error: invalid type conversion
convert1.go:56:13: error: invalid type conversion
convert1.go:57:11: error: invalid type conversion
convert1.go:58:11: error: invalid type conversion
convert1.go:64:13: error: invalid type conversion
convert1.go:68:12: error: invalid type conversion (cannot use type Tstring as type Tint64)
convert1.go:72:12: error: invalid type conversion
convert1.go:73:13: error: invalid type conversion
convert1.go:76:11: error: invalid type conversion (cannot use type Tbyte as type Trune)
convert1.go:77:12: error: invalid type conversion (cannot use type Tbyte as type Tint64)
convert1.go:80:12: error: invalid type conversion
convert1.go:82:13: error: invalid type conversion
convert1.go:84:11: error: invalid type conversion (cannot use type Trune as type Tbyte)
convert1.go:86:12: error: invalid type conversion (cannot use type Trune as type Tint64)
convert1.go:88:6: error: invalid type conversion (cannot use type Tint64 as type string)
convert1.go:89:12: error: invalid type conversion
convert1.go:90:12: error: invalid type conversion
convert1.go:92:13: error: invalid type conversion (cannot use type Tint64 as type Tstring)
convert1.go:93:11: error: invalid type conversion (cannot use type Tint64 as type Tbyte)
convert1.go:94:11: error: invalid type conversion (cannot use type Tint64 as type Trune)
fixedbugs/bug195.go:9:21: error: interface contains embedded non-interface
fixedbugs/bug195.go:12:21: error: interface contains embedded non-interface
fixedbugs/bug195.go:15:15: error: interface contains embedded non-interface
fixedbugs/bug195.go:18:2: error: invalid recursive interface
fixedbugs/bug195.go:26:2: error: invalid recursive interface
fixedbugs/bug195.go:22:2: error: invalid recursive interface
fixedbugs/bug251.go:15:2: error: invalid recursive interface
fixedbugs/bug251.go:11:2: error: invalid recursive interface
fixedbugs/bug374.go:18:34: error: use of undefined type ‘xxxx’
fixedbugs/bug374.go:16:5: error: incompatible type in initialization (incompatible type for method ‘m’ (different number of parameters))
fixedbugs/bug383.go:11:2: error: expected boolean expression
fixedbugs/bug383.go:12:2: error: expected boolean expression
fixedbugs/bug386.go:10:25: error: incompatible type for return value 1 (type has no methods)
fixedbugs/bug386.go:12:25: error: incompatible type for return value 1 (type has no methods)
fixedbugs/bug388.go:12:10: error: invalid named/anonymous mix
fixedbugs/bug388.go:17:19: error: non-name on left side of ‘:=’
fixedbugs/bug388.go:22:9: error: non-name on left side of ‘:=’
fixedbugs/bug388.go:27:10: error: expected type
fixedbugs/bug388.go:32:9: error: expected type
fixedbugs/bug388.go:23:14: error: reference to field ‘i’ in object which has no fields or methods
fixedbugs/bug388.go:18:18: error: invalid use of type
fixedbugs/bug389.go:12:5: error: incompatible type in initialization (different parameter types)
fixedbugs/bug390.go:15:24: error: expected integer, floating, or complex type
fixedbugs/bug394.go:10:1: error: expected declaration
fixedbugs/bug397.go:12:2: error: incompatible type for element 2 key in map construction
switch3.go:18:2: error: incompatible types in binary expression
switch3.go:22:2: error: incompatible types in binary expression
switch3.go:28:2: error: map can only be compared to nil
switch3.go:35:2: error: slice can only be compared to nil
switch3.go:42:2: error: func can only be compared to nil
syntax/else.go:11:9: error: expected ‘if’ or ‘{’
typeswitch2.go:15:2: error: duplicate type in switch
typeswitch2.go:19:2: error: duplicate type in switch
typeswitch2.go:26:2: error: duplicate type in switch
typeswitch2.go:40:9: error: ‘t’ declared and not used
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5573073
chan.go:11:1: error: unexpected ‘}’ in channel type
chan.go:13:16: error: unexpected ‘)’ in channel type
chan.go:16:16: error: unexpected comma in channel type
R=golang-dev, rsc1
CC=golang-dev
https://golang.org/cl/4313055
vareq.go:10:25: error: expected ';' or '}' or newline
vareq1.go:9:24: error: expected ';' or newline after top level declaration
R=rsc
CC=golang-dev
https://golang.org/cl/2132045
With the recursive descent parser that gccgo uses, I think
that it doesn't make sense to try to match a statement where a
statement is not expected. If the construct is not a
statement, you will just get bizarre error messages.
topexpr.go:9:1: error: expected declaration
topexpr.go:14:1: error: expected declaration
topexpr.go:19:1: error: expected declaration
R=rsc, r2
CC=golang-dev
https://golang.org/cl/2175041
bug121.go:12:3: error: name list not allowed in interface type
bug121.go:16:2: error: expected signature or type name
semi1.go:10:76: error: unexpected semicolon or newline before ‘{’
semi1.go:10:5: error: reference to undefined name ‘x’
semi1.go:10:8: error: reference to undefined name ‘y’
semi1.go:12:3: error: reference to undefined name ‘z’
semi2.go:10:79: error: unexpected semicolon or newline before ‘{’
semi2.go:10:9: error: reference to undefined name ‘x’
semi3.go:10:79: error: unexpected semicolon or newline before ‘{’
semi3.go:10:6: error: reference to undefined name ‘x’
semi3.go:10:9: error: reference to undefined name ‘y’
semi3.go:10:12: error: reference to undefined name ‘z’
semi3.go:12:3: error: reference to undefined name ‘z’
semi4.go:11:2: error: unexpected semicolon or newline before ‘{’
semi4.go:10:6: error: reference to undefined name ‘x’
semi4.go:12:3: error: reference to undefined name ‘z’
semi5.go:10:1: error: unexpected semicolon or newline before ‘{’
semi7.go:11:2: error: unexpected semicolon or newline before ‘else’
semi7.go:10:5: error: reference to undefined name ‘x’
slice.go:9:11: error: missing lower bound in slice expression
slice.go:9:9: error: reference to undefined name ‘y’
slice.go:9:12: error: reference to undefined name ‘z’
R=rsc
CC=golang-dev
https://golang.org/cl/201061
* example-based syntax errors (go.errors)
* enable bison's more specific errors
and translate grammar token names into
tokens like ++
* test cases
R=ken2, r, ken3
CC=golang-dev
https://golang.org/cl/194085
